Taxonomic notes on Japanese Blattaria I. : A new Blattella closely allied to Blattella germanica

Abstract

A wild Blattella species apparently closely allied to the German cockroach, Blattella germanica Linne, has been known to occur in the coast area of western part of Japan. Furukawa (1948) supposed it to be the same with Blattella bisignata Brunner von Wattenvyl which was, however, described from Burma and now believed to be a geographical race of the small-sized South Asiatic Blattella lituricollis Walker. The present author came to the conclusion that this species represents a distinct, undescribed species, and named it as Blattella nipponica sp. nov. The main distinguishing characteristics are, when compared with those of Bl. germanica, as follows : 1. The paired black stripes on the prothorax broad and always show the tendency to access each other at the posterior ends (Fig.1) 2. The structure of the dorsal glands of the male 7 and 8 abdominal segments quite different, and there are numerous short bristles on 7 segment (Fig. 2, 3). 3.The male subgenital plate short and broad, the assymmetrical depression, when seen from ventral side, is shallow; the two styli situated closely (Fig. 4, 5). 4. The left epiphallus of male genitalia ending in a claw which is sparcely punctured (Fig.6). 5. The female supraanal plate, in a fresh or alcoholic specimen, slightly emarginated at the posterior end, with two dark spot at the base (Fig.7). This species distributes in the southwestern part of Japan as far south as Tanegashima but never found in Ryukyus (Fig. 9). The type specimens are selected from Tanegashima material. The life-history is not still sufficiently made known, they are found in the roadside grass-land of seaside, or under dead leaves collected at forest edge, or among decayed vegetable matter in cultivated land. Overwintering is made during later larval instars and two generations are supposed to be passed in a year. These can be bred in a laboratory by similar method to the German cockroach. It may be interesting to note that this species can fly while the German cockroach does not; attempts to hybridize both failed so far.